He keeps asking to play it on the Mac as it's apparently better than the PS4 version, I have searched the web and found many links but nothing looks official
Why would you play through a PC, VM, or Bootcamp when the native Mac version of Minecraft is no different and runs great (and both contain their own optimized Java now so no need for that to even be installed on the Mac)?
The earlier link: https://minecraft.net/
Is also official, but obviously specific to Minecraft.
Regardless of the site, you will need to create a Mojang account and purchase the game on that account. The Mojang account is then needed to log into and play the game. Note that the name chosen will be what is displayed in game.